The use of external fixation or stabilizing frames for retaining broken or fractured bones in a particularly desired orientation or configuration is widely known and commonly employed. However, in most typical prior art external frame constructions, particularly frame constructions employed to stabilize broken or fractured bones, a variety of clamps and holding rods are employed to enable the surgeon to position the broken/fractured bones in a precisely desired position or orientation, and then allowing the bone to be retained in that position or orientation for healing.
Although wide variety of frame structures and clamp systems have been used for this purpose, one common problem existing with most prior art stabilizing frame constructions is the inability to allow the frame construction to be easily adjustable during its assembly. In this regard, in most applications, anchor pins or anchor screws are mounted in a fractured bone, extending outwardly therefrom for attachment to a frame assembly. Clamp members are mounted to the anchor pins or anchor screws with a plurality of rod members being mounted to a plurality of interconnecting clamps to establish the desired stabilizing frame assembly. However, during the creation of the frame structure, which must be maintained in a precise orientation in order to assure that the bone fracture is precisely aligned for healing, these prior art frame systems have been found to be incapable of being retained in a desired position unless securely clamped. As a result, repeated tightening and loosening of the clamps is required before the precisely desired frame structure is fully assembled.
In those instances where the frame assembly being created has an insufficient clamping force applied to the rod members for securing the rod members in the clamp, slippage of the rod in the clamp often occurs. This causes the frame structure to become improperly aligned, resulting in repeated efforts to recreate and readjust the frame.
In addition, since improper alignment may cause the bone elements to be dislodged from the desired position or may impose improper forces upon the bone elements, the slippage caused by loose rods cannot be tolerated. As a result, the arduous task of clamping and unclamping every interconnection must be imposed upon the physician, in order to assure a frame structure is created having the precisely desired configuration and orientation and is maintained in that position throughout its assembly.
In an attempt to satisfy this need, some clamp members incorporate coil springs to prevent slippage. However, these systems do not provide the desired result and are expensive to produce.
Therefore, it is a principal object of the present invention to provide an adjustable frame structure for stabilizing broken or fractured bones which is capable of being the easily constructed by attaching two anchoring pins or screws, with all compounds thereof being retained in any desired position, without the application of final clamping forces.
Another object to the present invention is to provide an adjustable frame structure having the characteristic features described above which allows ease of assembly while still assuring secure, clamped interengagement of all components when required.
Another object of the present invention is to provide an adjustable frame structure having the characteristic features described above which automatically incorporates friction engagement between sliding components for maintaining such component in any position without requiring a clamping force.
Other and more specific objects will impart the obvious and will impart appear hereinafter.